/*
 * Copyright (C) 2001-2008 Jacek Sieka, arnetheduck on gmail point com
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#if !defined(SIMPLE_XML_H)
#define SIMPLE_XML_H

#include "Exception.h"

#include "File.h"

namespace dcpp {

STANDARD_EXCEPTION(SimpleXMLException);

/**
 * This class reads an XML and calls a callback for each
 * element encountered.
 * It is in no way a full XML parser.
 */
class SimpleXMLReader {
public:
	struct CallBack {
		virtual ~CallBack() { }
		virtual void startTag(const string& name, StringPairList& attribs, bool simple) = 0;
		virtual void endTag(const string& name, const string& data) = 0;

	protected:
		static const string& getAttrib(StringPairList& attribs, const string& name, size_t hint) {
			hint = min(hint, attribs.size());

			StringPairIter i = find_if(attribs.begin() + hint, attribs.end(), CompareFirst<string, string>(name));
			if(i == attribs.end()) {
				i = find_if(attribs.begin(), attribs.begin() + hint, CompareFirst<string, string>(name));
				return ((i == (attribs.begin() + hint)) ? Util::emptyString : i->second);
			} else {
				return i->second;
			}
		}
	private:
		CallBack& operator=(const CallBack&);
	};

	SimpleXMLReader(CallBack* callback) : cb(callback), encoding(Text::utf8) { }
	virtual ~SimpleXMLReader() { }

	string::size_type fromXML(const string& tmp, const string& n = Util::emptyString, string::size_type start = 0, int depth = 0) throw(SimpleXMLException);
private:
	StringPairList attribs;
	string data;

	CallBack* cb;
	string encoding;

	string::size_type loadAttribs(const string& name, const string& tmp, string::size_type start) throw(SimpleXMLException);
	static const int maxNesting = 200;
};

/**
 * A simple XML class that loads an XML-ish structure into an internal tree
 * and allows easy access to each element through a "current location".
 */
class SimpleXML
{
public:
	SimpleXML() : root("BOGUSROOT", Util::emptyString, NULL), current(&root), found(false) {
		resetCurrentChild();
	}
	~SimpleXML() { }

	void addTag(const string& aName, const string& aData = Util::emptyString) throw(SimpleXMLException);
	void addTag(const string& aName, int aData) throw(SimpleXMLException) {
		addTag(aName, Util::toString(aData));
	}
	void addTag(const string& aName, int64_t aData) throw(SimpleXMLException) {
		addTag(aName, Util::toString(aData));
	}

	template<typename T>
	void addAttrib(const string& aName, const T& aData) throw(SimpleXMLException) {
		addAttrib(aName, Util::toString(aData));
	}

	void addAttrib(const string& aName, const string& aData) throw(SimpleXMLException);
	void addAttrib(const string& aName, bool aData) throw(SimpleXMLException) {
		addAttrib(aName, string(aData ? "1" : "0"));
	}

	template <typename T>
	void addChildAttrib(const string& aName, const T& aData) throw(SimpleXMLException) {
		addChildAttrib(aName, Util::toString(aData));
	}
	void addChildAttrib(const string& aName, const string& aData) throw(SimpleXMLException);
	void addChildAttrib(const string& aName, bool aData) throw(SimpleXMLException) {
		addChildAttrib(aName, string(aData ? "1" : "0"));
	}

	const string& getData() const {
		dcassert(current != NULL);
		return current->data;
	}

	void stepIn() throw(SimpleXMLException) {
		checkChildSelected();
		current = *currentChild;
		currentChild = current->children.begin();
		found = false;
	}

	void stepOut() throw(SimpleXMLException) {
		if(current == &root)
			throw SimpleXMLException("Already at lowest level");

		dcassert(current->parent != NULL);

		currentChild = find(current->parent->children.begin(), current->parent->children.end(), current);

		current = current->parent;
		found = true;
	}

	void resetCurrentChild() throw() {
		found = false;
		dcassert(current != NULL);
		currentChild = current->children.begin();
	}

	bool findChild(const string& aName) throw();

	const string& getChildData() const throw(SimpleXMLException) {
		checkChildSelected();
		return (*currentChild)->data;
	}

	const string& getChildAttrib(const string& aName, const string& aDefault = Util::emptyString) throw(SimpleXMLException) {
		checkChildSelected();
		return (*currentChild)->getAttrib(aName, aDefault);
	}

	int getIntChildAttrib(const string& aName) throw(SimpleXMLException) {
		checkChildSelected();
		return Util::toInt(getChildAttrib(aName));
	}
	int64_t getLongLongChildAttrib(const string& aName) throw(SimpleXMLException) {
		checkChildSelected();
		return Util::toInt64(getChildAttrib(aName));
	}
	bool getBoolChildAttrib(const string& aName) throw(SimpleXMLException) {
		checkChildSelected();
		const string& tmp = getChildAttrib(aName);

		return (tmp.size() > 0) && tmp[0] == '1';
	}

	void fromXML(const string& aXML) throw(SimpleXMLException);
	string toXML() { string tmp; StringOutputStream os(tmp); toXML(&os); return tmp; }
	void toXML(OutputStream* f) throw(FileException) { if(!root.children.empty()) root.children[0]->toXML(0, f); }

	static const string& escape(const string& str, string& tmp, bool aAttrib, bool aLoading = false, const string &encoding = Text::utf8) {
		if(needsEscape(str, aAttrib, aLoading, encoding)) {
			tmp = str;
			return escape(tmp, aAttrib, aLoading, encoding);
		}
		return str;
	}
	static string& escape(string& aString, bool aAttrib, bool aLoading = false, const string &encoding = Text::utf8);
	/**
	 * This is a heuristic for whether escape needs to be called or not. The results are
 	 * only guaranteed for false, i e sometimes true might be returned even though escape
	 * was not needed...
	 */
	static bool needsEscape(const string& aString, bool aAttrib, bool aLoading = false, const string &encoding = Text::utf8) {
		return Util::stricmp(encoding, Text::utf8) != 0 || (((aLoading) ? aString.find('&') : aString.find_first_of(aAttrib ? "<&>'\"" : "<&>")) != string::npos);
	}
	static const string utf8Header;
private:
	class Tag {
	public:
		typedef Tag* Ptr;
		typedef vector<Ptr> List;
		typedef List::iterator Iter;

		/**
		 * A simple list of children. To find a tag, one must search the entire list.
		 */
		List children;
		/**
		 * Attributes of this tag. According to the XML standard the names
		 * must be unique (case-sensitive). (Assuming that we have few attributes here,
		 * we use a vector instead of a (hash)map to save a few bytes of memory and unnecessary
		 * calls to the memory allocator...)
		 */
		StringPairList attribs;

		/** Tag name */
		string name;

		/** Tag data, may be empty. */
		string data;

		/** Parent tag, for easy traversal */
		Ptr parent;

		Tag(const string& aName, const StringPairList& a, Ptr aParent) : attribs(a), name(aName), data(), parent(aParent) {
		}

		Tag(const string& aName, const string& d, Ptr aParent) : name(aName), data(d), parent(aParent) {
		}

		const string& getAttrib(const string& aName, const string& aDefault = Util::emptyString) {
			StringPairIter i = find_if(attribs.begin(), attribs.end(), CompareFirst<string,string>(aName));
			return (i == attribs.end()) ? aDefault : i->second;
		}
		void toXML(int indent, OutputStream* f);

		void appendAttribString(string& tmp);
		/** Delete all children! */
		~Tag() {
			for(Iter i = children.begin(); i != children.end(); ++i) {
				delete *i;
			}
		}

	private:
		Tag(const Tag&);
		Tag& operator=(Tag&);
	};

	class TagReader : public SimpleXMLReader::CallBack {
	public:
		TagReader(Tag* root) : cur(root) { }
		virtual bool getData(string&) { return false; }
		virtual void startTag(const string& name, StringPairList& attribs, bool simple) {
			cur->children.push_back(new Tag(name, attribs, cur));
			if(!simple)
				cur = cur->children.back();
		}
		virtual void endTag(const string&, const string& d) {
			cur->data = d;
			if(cur->parent == NULL)
				throw SimpleXMLException("Invalid end tag");
			cur = cur->parent;
		}

		Tag* cur;
	};

	SimpleXML(const SimpleXML&);
	SimpleXML& operator=(const SimpleXML&);

	/** Bogus root tag, should have only one child! */
	Tag root;

	/** Current position */
	Tag::Ptr current;

	Tag::Iter currentChild;

	void checkChildSelected() const throw() {
		dcassert(current != NULL);
		dcassert(currentChild != current->children.end());
	}

	bool found;
};

} // namespace dcpp

#endif // !defined(SIMPLE_XML_H)